MapMyFlatTyre


Eleven year-old tyres and the bush don’t mix.

My spiffy mountain bike is actually a 2001 model Cannondale Super V 700 SX.  So little had I used it that I was still on the original tyres until last week.

I had explored more tracks in Mulligan’s Flat Reserve and had just left the fenced area, taking a short burst along the 200m to rejoin the bike path.  Then the rear tyre exploded.  I had time to slow down and get out of the pedals and made a dignified dismount.  I didn’t have to look far to find a flap in the tyre as large as my little finger nail.

Over the gate was a large, clean concrete pad; a nice work surface.  Now to remember how to remove the back wheel!  The rear brake is a hydraulic “caliper” with a piston and pad on each side.  The quick release lever removes one side of the brake from the stay to offer tyre clearance.  The rear wheel quick release is otherwise conventional.  I used my new tyre levers and self-adhesive patch to patch the somewhat smaller hole on the tube.  The tube was so lightweight as to make replacing it in the tyre a bit of a task.  Pumped up a reasonable amount to get home in a slightly squirmy fashion.

Big hole
Is not getting any smaller
Hole no smaller from this angle
Big hole

Got home and pumped the tyre up to 40 psi to test the patch seal.  The next morning the tube had held all of its air, but the tyre was distended at the hole.  I could patch it from the inside using a vulcanising patch and then seal the outside somehow, but the tyre was already 12 years old and showing signs of age, if not wear.

Down to the bike shop (oh the pain of spending time in a bike shop!) I chose a pair of Maxxis CrossMark tyres and new thorn-proof tubes.  The swap was easy after my practice the night before. The front wheel is even easier; the Lefty fork allows tyre change without removing the wheel!

One of these tubes is lightweight and one is thorn-proof.  Can you guess which is which?
One of these tubes is lightweight and one is thorn-proof. Can you guess which is which?
New tyres and tubes
New tyres and tubes

After fitting the front tyre, I noticed the direction indicator. With the bike upside down I couldn’t for the life of me work out which way it had to go on. Some tyre patterns work in opposite directions for front and rear applications, so I toyed with the idea of putting the rear on the other way.  As it happened,, I’d guessed correctly.

The next night I rode a long road course on my new tyres, hitting top gear and 47 km/h in the process.  So smooth, so light, so quiet. No longer are pedestrians¹ warned of my approach by the buzzing of knobbly tyres. I’ll have to pop to the bike shop again, to buy a bell.

Old mud tyre, meet metro-sexual tyre
Old mud tyre, meet metro-sexual tyre

1: Riding on the footpath is legal in Canberra (even for adults) in all but two places: The entrance to Parliament House and some other place that’s signposted but escapes me at the moment.

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